I like what “One Tree Hill” has done, leaping ahead four years with the storyline. The characters, who graduated high school at the end of Season Four, skipped the dreaded college years completely and are in the middle of young adult life in Season Five. Not only do the actors look their age, there are plenty of interesting plot turns to explore. The best thing about the re-christened “One Tree Hill,” however, is the arrival of the show’s youngest character — Jamie, Nathan and Haley’s four-year-old. The kid is played by Jackson Brundage, a terrific and adorable child actor, who stole every scene he was in in the first two episodes. Remember the name.